Add base::ThreadTaskRunner class.

base/thread_task_runner_handle.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_THREAD_TASK_RUNNER_HANDLE_H_
+#define BASE_THREAD_TASK_RUNNER_HANDLE_H_
+
+#include "base/base_export.h"
+#include "base/memory/ref_counted.h"
+
+namespace base {
+
+class SingleThreadTaskRunner;
+
+// ThreadTaskRunner stores reference to the main task runner for each

[Ami GONE FROM CHROMIUM, 2012/05/08 01:30:14]

s/stores/stores a/

[willchan no longer on Chromium, 2012/05/08 02:35:06]

s/ThreadTaskRunner/ThreadTaskRunnerHandle/

[Sergey Ulanov, 2012/05/09 18:34:11]

Done.

[Sergey Ulanov, 2012/05/09 18:34:11]

Done.

+// thread. Not more than one of these objects created per

[Ami GONE FROM CHROMIUM, 2012/05/08 01:30:14]

s/created/can be created/

[Sergey Ulanov, 2012/05/09 18:34:11]

Done.

[Sergey Ulanov, 2012/05/09 18:34:11]

Done.

+// thread. After an instance of this object is created the Get()
+// function will be returning the |task_runner| specified in the

[Ami GONE FROM CHROMIUM, 2012/05/08 01:30:14]

s/be returning/return/

[Sergey Ulanov, 2012/05/09 18:34:11]

Done.

+// constructor.
+class BASE_EXPORT ThreadTaskRunnerHandle {
+ public:
+  // Gets the SingleThreadTaskRunner for the current thread.
+  static scoped_refptr<SingleThreadTaskRunner> Get();
+
+  ThreadTaskRunnerHandle(
+      const scoped_refptr<SingleThreadTaskRunner>& task_runner);
+  ~ThreadTaskRunnerHandle();
+
+ private:
+  scoped_refptr<SingleThreadTaskRunner> task_runner_;
+};
+
+}  // namespace base
+
+#endif  // BASE_THREAD_TASK_RUNNER_HANDLE_H_